How difficilt to fix wet core in the deck?

[alex_sauvage]

I am looking at Beneteau of early 1990s vintage and the survey indicates half a dozen of spots on the deck and cabin top with elevated moisure. From 10" in diameter to 2 feet by 2 feet. And some delamination in places. How much of an issue it is and how difficult/labour intensive the fix is? I never dealt with a wet core, so don't have a good feel for it. If someone had experience dealing with such an issue I would greatly appreciate an advice

[wingssail]

Originally Posted by alex_sauvage

I am looking at Beneteau of early 1990s vintage and the survey indicates half a dozen of spots on the deck and cabin top with elevated moisure. From 10" in diameter to 2 feet by 2 feet. And some delamination in places. How much of an issue it is and how difficult/labour intensive the fix is? I never dealt with a wet core, so don't have a good feel for it. If someone had experience dealing with such an issue I would greatly appreciate an advice

These jobs are fairly straight forward if you are just brave enough to jump in and do it. I've done several over the 33 years we've had this boat, some areas big, some small.

The most difficult part on a production boat is dealing with the molded-in nonskid pattern of the deck. You have to remove the skin, usually top, and later replace it leaving a scar. Skilled hand work can reproduce the non-skid pattern so that it is barely noticeable. A very small area can be done from below saving the top skin but that brings in it's own problems.

Steps:
1. Carefully and thoroughly survey the deck area by tapping and mark the soft spot.

2. Remove any hardware.

3. Cut a shallow ditch 3/4" wide in the skin completely around the soft area with an angle grinder using a cut off blade then cut through the skin.

4. Lift off the skin, keeping it intact, and completely dig out the soft core. Dry, and prep the entire area.

5. Install new core (over epoxy paste) with small wood blocks, (I've used soft wood such as pine) and fill all voids with epoxy and filler. This may take several passes if the deck is slanted because the epoxy tends to run out the low side. Make it thick.

6. Reinstall the top skin using plenty of epoxy and paste. Weight it down with sand bags.

7. Repair the ditch with epoxy and glass, then epoxy filler and repair the scar.

8. Paint.

9. Reinstall hardware.

This blog post contains images showing how we did this type of work last year on a large area: https://wingssail-images.blogspot.co...ct-update.html
I did this job myself in four days.

[guyrj33]

I suggest filling with a non water absorbing core such as divinycell.
Use epoxy resin.
flexmold makes a flexible sheet mold to reproduce factory non-skid patterns.
Read everything you can about making core repairs.

[alex_sauvage]

Thank you guys, it is very informative. I thought it is generally done from down below to preserve toplayer. It is obviouly easier to do from the top, but I guess one will need to restore gelcoat and nonskid

[zemurray]

A spot on my boat was done by the previous owner prior to sale. He provided pics of the process to document the repair. They did it from below, since the boat has a removable headliner. I think that might make a difference on which direction you would go. The pics look real straight forward doing from below. They just cut the section as described above and used marine plywood and layers of fiber glass and resin, and wedged in some supports to the floor to keep pressure on it until it cured. Put headliner back up, and no cosmetic work needed.

Are the decks on actually squishy? If you cant feel it squish under foot, then why not just make sure the source of the water entry is resolved and live with it until it needs to be dealt with?

[dick sargent]

I saw an extensive repair of a wet core deck that was so successful and simple I would be tempted to try it. Zerk fittings were installed to inject a thin penetrating epoxy into the balsa area. After use the zerk fitting holes were plugged with teak plugs. The deck was a patterned non-skid deck and the holes were drilled in a pattern too, so not a distraction. Btw It was on a Colombia 36, that a couple sailed around the world more than once.

[Glassdog]

There is a wonderful YouTube blog called “SailLife” by a guy named Mads in Denmark, he is a meticulous craftsman and he recored his entire deck from above using new foam core and he is very detailed in his videos so I would suggest you check him out and you will be able to see just what is involved in re- coring. Good luck to you

[zemurray]

Originally Posted by dick sargent

I saw an extensive repair of a wet core deck that was so successful and simple I would be tempted to try it. Zerk fittings were installed to inject a thin penetrating epoxy into the balsa area. After use the zerk fitting holes were plugged with teak plugs. The deck was a patterned non-skid deck and the holes were drilled in a pattern too, so not a distraction. Btw It was on a Colombia 36, that a couple sailed around the world more than once.

Have a link, this sounds interesting for spot repairs ?

[Michael Pope]

The big question is ---What type of Core ?? If it is balsa Oh Boy I hate those jobs as Balsa rots quickly with fresh water and turns into black porridge!! But that is not the bad part ---- the Mold has fine roots or filaments that go past the face of the rot some times 18 inches past and you can not see them. I did one 38 footer with a massive area around the mast . I barricaded the deck so nothing could walk on it and stuck little wood shaped ribs on it with silicon to hold the shape of the top skin because it was in good condition. Took down the headliner carefully ground around the edge (4 1/2" grinder) and most of the nasty stuff and remnants of core fell down. Grind it all smooth. Vacuum bag New fitted Foam core in multiple setups with epoxy. Biggest problem is making the top skin Vacuum proof with no leaks. You make a lot of bags. Use Thickened epoxy on the Top of the core and Brown Micro balloon butter at the edges. Tidy up the inner face so a laminate will lay on it and bag an inner skin. Two months of hell with epoxy in your ears hair etc. and there you are at least it will not rot and is stiffer and stronger than it was new. Now you want to get paid and the interior is a mess! Happy boating Mike Pope

[valhalla360]

If you have easy access from below, that is generally going to be easier as the headliner will cover the lack of fine finish on the fiberglass surface.

If it's on the top, yeah, you need a little bit of finesse to get a good looking repair but the basic repair is pretty easy.

[Tillsbury]

Assuming you’re still looking at it, just run away and buy a boat without the problem, unless you like diy and are getting it almost free.

[admiralslater]

I agree with Tillsbury it needs to be cheap. That said the bid difference between a topside and interior repair would be the requirement to vacuum the coring into place .

[alex_sauvage]

Originally Posted by Tillsbury

Assuming you’re still looking at it, just run away and buy a boat without the problem, unless you like diy and are getting it almost free.

Thank you guys, it sounds like a good advice! But I am greatful to everyone for letting me know how to approach those issues in a future.